Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

590
FXUS63 KLOT 241728
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1228 PM CDT Sun May 24 2026

.KEY MESSAGES...

- Potential for dense fog to develop over Lake Michigan tonight
  and affect locations along the shore.

- Above normal temperatures through the early part of the week,
  though cooler near Lake Michigan.

&&

.DISCUSSION...
Issued at 226 AM CDT Sun May 24 2026

Festering showers continue to bubble up west of the forecast
area, closer to a surface front analyzed along or just west of
the Mississippi River. With weaker forcing, coverage is a little
lacking leading to more isolated to localized clusters
developing. A few lightning strikes may be possible, but with
limited instability, confidence low. Some of these showers may
continue into the area west of the Fox Valley through the next
couple of hours.

The previously mentioned front is expected to sweep across the
area through the early morning, exiting to the east around
midday. Coverage of showers along and ahead of the front is
expected to increase closer to daybreak along the better
forcing with the arrival of a mid level wave. Southerly winds
will advect in an almost tropical air mass with precipitable
water amounts north of 1.50 inches. With slow storm motions
(around 20 mph or less) nearly parallel to the front, the
primary threat is for downpours and even localized torrential
rainfall. Widespread flash flooding is not expected, but with
intense rain rates (locally greater than an inch per hour) and
possible training there is a chance that there could be
localized ponding in poor drainage areas. Additionally, model
soundings depicting tall, skinny CAPE allows for the potential
for some embedded thunder as the front moves through, though
higher coverage of storms is expected along and east of I-55
after daybreak.

Drier conditions are expected in the afternoon in the wake of
the front through Tuesday. Models are suggesting a weak 700 mb
wave moving across Iowa into lower southern Wisconsin late on
Monday. Given its projected track away from northern Illinois,
PoPs were kept dry and just something to monitor. Otherwise,
upper level ridging and surface high pressure will grow today
through Tuesday driving not just dry conditions but warm, above
normal temperatures. Lake breezes will help keep cooler
conditions cooler near the lake shoreline, but temperatures well
into the 80s can be expected farther inland.

Models are suggesting that by Wednesday morning, a near Omega
blocking pattern will set up in the mid-to-upper levels.
Ensembles are still suggesting that a weak 700 mb wave will move
northward from the Gulf to the mid Mississippi River Valley.
This could provide the next chances for rain and storms, but
models noticeably keep the better chances farther south
compared to 24 hours prior. As the stagnant pattern remains
toward the end of the week, conditions are looking dry and
seasonable beyond Thursday.

DK

&&

.AVIATION /18Z TAFS THROUGH 00Z TUESDAY/...
Issued at 1227 PM CDT Sun May 24 2026

Initial clearing behind this morning`s rain has allowed for
diurnal mixing into SCT/BKN MVFR cumulus early this afternoon.
These clouds should lift while dissipating over the next couple
hours.

Light NW winds at TAF issuance will turn E/ESE up to 10 knots
with a lake breeze mid to late afternoon (roughly 20Z at MDW and
21Z at ORD). As high pressure shifts over the terminals this
evening, winds will settle in the SE quadrant under 5 knots or
become calm. Winds will turn SSW late tonight, then increase to
around 10 knots on Monday.

Will need to monitor for the potential for dense fog over Lake
Michigan late this afternoon and overnight. Given the weak flow,
the lake fog should not advect over ORD/MDW, but radiational BR
or BCFG will remain possible overnight through daybreak Monday.
Included a mention of FEW IFR stratus at MDW given the
proximity of FG to the east. Additionally, cannot fully rule out
the development of BR/FG south of the Chicago metro late
tonight. Given low-level flow veering SSW during this time,
dissipating IFR stratus could advect to near MDW/GYY around
sunrise.

Kluber

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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